Bring back original video quality option

Telegram/SourceFiles/data/data_document.cpp

@@ -544,11 +544,12 @@ void DocumentData::setVideoQualities(
 		return;
 	}
 	const auto good = [&](not_null<DocumentData*> document) {
+		// Transcodes in alt_documents are always streamable,
+		// even if the supports_streaming flag is missing
 		return document->isVideoFile()
 			&& !document->dimensions.isEmpty()
 			&& !document->inappPlaybackFailed()
-			&& document->useStreamingLoader()
-			&& document->canBeStreamed();
+			&& document->useStreamingLoader();
 	};
 	ranges::sort(
 		qualities,
@@ -578,18 +579,67 @@ void DocumentData::setVideoQualities(
 	}
 	qualities.erase(qualities.begin() + count, qualities.end());
 	if (!qualities.empty()) {
-		if (const auto mine = resolveVideoQuality()) {
-			if (mine > qualities.front()->resolveVideoQuality()) {
-				qualities.insert(begin(qualities), this);
+		auto transcodeMax = 0;
+		for (const auto &quality : qualities) {
+			const auto qres = quality->resolveVideoQuality();
+			if (qres > transcodeMax) {
+				transcodeMax = qres;
 			}
 		}
+		const auto attributesSize = isVideoFile() ? dimensions : QSize();
+		const auto attributesQuality = attributesSize.isEmpty()
+			? 0
+			: std::min(attributesSize.width(), attributesSize.height());
+
+		// Heuristic: Trust attributes resolution unless it blatantly
+		// contradicts server-side transcodes (>1.5x delta)
+		auto mine = (transcodeMax > 0
+			&& (attributesQuality < transcodeMax
+				|| attributesQuality > transcodeMax * 1.5))
+			? transcodeMax
+			: attributesQuality;
+		if (mine) {
+			qualities.insert(begin(qualities), this);
+		}
 	}
 	data->qualities = std::move(qualities);
 }
 
 int DocumentData::resolveVideoQuality() const {
-	const auto size = isVideoFile() ? dimensions : QSize();
-	return size.isEmpty() ? 0 : std::min(size.width(), size.height());
+	if (const auto data = video()) {
+		if (!data->realVideoSize.isEmpty()) {
+			// Always trust FFmpeg-parsed physical resolution
+			const auto size = data->realVideoSize;
+			return std::min(size.width(), size.height());
+		}
+		const auto attributesSize = isVideoFile() ? dimensions : QSize();
+		const auto attributesQuality = attributesSize.isEmpty()
+			? 0
+			: std::min(attributesSize.width(), attributesSize.height());
+		if (!data->qualities.empty()) {
+			auto transcodeMax = 0;
+			for (const auto &quality : data->qualities) {
+				if (quality != this) {
+					const auto qres = quality->resolveVideoQuality();
+					if (qres > transcodeMax) {
+						transcodeMax = qres;
+					}
+				}
+			}
+			if (transcodeMax > 0) {
+				// Trust transcodes if attributes appear fake
+				if (attributesQuality < transcodeMax
+					|| attributesQuality > transcodeMax * 1.5) {
+					return transcodeMax;
+				}
+				return attributesQuality;
+			}
+		}
+	}
+	const auto attributesSize = isVideoFile() ? dimensions : QSize();
+	return attributesSize.isEmpty()
+		? 0
+		: std::min(attributesSize.width(), attributesSize.height());
 }
 
 auto DocumentData::resolveQualities(HistoryItem *context) const
@@ -611,19 +661,30 @@ not_null<DocumentData*> DocumentData::chooseQuality(
 		return this;
 	}
 	const auto height = int(request.height);
-	auto closest = this;
-	auto closestAbs = std::abs(height - resolveVideoQuality());
-	auto closestSize = size;
+	if (height >= Media::kVideoQualityOriginalOffset) {
+		return this;
+	}
+
+	auto closest = (DocumentData*)nullptr;
+	auto closestAbs = -1;
+	auto closestSize = -1;
+
 	for (const auto &quality : list) {
-		const auto abs = std::abs(height - quality->resolveVideoQuality());
-		if (abs < closestAbs
-			|| (abs == closestAbs && quality->size < closestSize)) {
+		const auto qres = quality->resolveVideoQuality();
+		const auto abs = std::abs(height - qres);
+		// Prefer Original if it fits target resolution best,
+		// falling back to transcode only on exact matches
+		if (!closest
+			|| abs < closestAbs
+			|| (abs == closestAbs && (quality->size < closestSize
+				|| (closest == this && quality != this)))) {
 			closest = quality;
 			closestAbs = abs;
 			closestSize = quality->size;
 		}
 	}
-	return closest;
+
+	return closest ? closest : this;
 }
 
 void DocumentData::validateLottieSticker() {